Charles H. Spurgeon on Psalms 104:10

He sendeth the springs into the valleys, which run among the hills. This is a beautiful part of the Lord's arrangement of the subject waters: they find vents through which they leap into liberty where their presence will be beneficial in the highest degree. Depressions exist in the sides of the mountains, and down these the water brooks are made to flow, often taking their rise at bubbling fountains which issue from the bowels of the earth. It is God who sends these springs even as a gardener makes the water courses, and turns the current with his foot. When the waters are confined in the abyss the Lord sets their bound, and when they sport at liberty he sends them forth.